Sheave mounting for hoisting booms



June S, 1943- E. w. HOLMES 2,321,549

SHEAVE MOUNTING FOR HOISTING OOMS Filed Sept. 26,41941 3 Sheets-Sheet 1m t Kc) 'i o Qq j l i3 A @qu *Q m O J W r/ l wd n r/zesZW/ZW.;

June 8, 1943. E. w. HOLMES 2,321,549

SHEAVE MOUNTING FORHOISTING BOOMS Filed Sept. 26, 1941 3 Sheets-Sheet 2r 4. y ad M W f5 fi 4f f r mk l 57 3mm ,f// W `Iune 8, 1943. E, w HOLMES2,321,549

SHEAVE MOUNTING FOR HOISTING BOOMS Filed Sept. 26, 1941 3 Sheets-Sheet 3Patented June 8, 1943 SHEAVE MOUNTNG FOR HOISTING ROOMS ErnestWalterHolmes, Chattanooga, Tenn., as-v a signor to Ernest Holmes Company,Chattanooga, Tenn., a corporation of Tennessee Application september 26,1941', 's'.erialNo. 412,487

7 Claims.

The present invention relates to improvements in automobile service andwrecking trucks, and more especially to those of the type shown anddescribed in my prior U. S. patent, Reissue No. 14,720, grantedSeptember 2, 1919, in which derrick or hoisting mechanism embodying apair of companion booms is mounted on a truck or similar automotivevehicle, and is adapted to extricate automobiles from positions in whichthey may be left as the result of accidents and to tow or haulautomobiles to service stations or other desired destinations.

In the developments of wrecking trucks of this double boom type forheavy duty, each boomsupporting cable is passed around a sheave carriedby a link attached to the outer end of the boom in order that the boomcable may sustain greater loads imposed on the boom, but it has beenfound in practice that when the booms are locked together to hold themagainst lateral swinging, and the hoisting cable of one of the booms isemployed for hauling or pulling in a direction laterally of the boom, asfor example,

in pulling a disabled automobile back onto a road from a side thereofwhile the wrecking truck occupies a position longitudinally of the road,or substantially so, a` lateral stress was imposed upon the boom due tothe link connection of the boom cable sheave to the outer end of theboom, which caused the boom cable sheave to swing laterally of the boomunder the load applied thereto by the hoisting cable.

rI"he primary object of the present invention is to provide a novel andimproved sheave mounting for the derrick or hoisting mechanism ofservice or wrecking trucks oi this type whereby such objection isobviated, and an improved operation of the derrick or hoisting mechanismis attained. According to the present invention, the sheaves for theboom and hoisting cables are journaled coaxially or on the same shaft,and are swivelled to rotate on the longitudinal axis of the boom whichintersects or substantially intersects the common axis of the sheaves.The sheaves for the boom and hoisting cables are, therefore, free toswivel freely and in union about the longitudinal axis of the boom undera stress applied laterally of the boom by a load on the hoisting cablewhile pulling at an angle to the longitudinal axis of the wreckingtruck, thus- `avoiding imposing a lateral strain on the boom or any ofthe other parts of the apparatus under such conditions.

Another object of the present invention is to provide a novel andimproved means for swivelling the sheaves the outer rend of the boom,whereby the sheave mounting may benreadily applied to 0r removedfrom theboom when the.

`sheave is rotated into one position vabout the 1ongitudinal axis of theboom, but is securely locked against displacement fromsthe end oi theboom when thesheave mounting is rotated into the position it occupiesduring normal operation of the derrckor hoisting apparatus,- in whichlatter position it is held by the lhoisting cable suspended from itsrespective sheave. i Y

To these and other ends, the invention consists in certain improvementsand combinations 'and arrangements ofparts, all as will be hereinaftermore fully described, the features of no velty being pointed out moreparticularly in the claims at the end votkthis speciiication.

In the accompanying drawings:

Figure 1 is a side elevation vof a derrick or hoisting mechanism for aWrecking truck, the same embodying the present invention;-

Figure 2 is a top plan' viewfof therouter ends of the companion booms,the same being shown locked together;

Figure 3 is a side elevation, partly in vertical section, of the outerend of onevof the booms, showing Vthe improved sheave mounting appliedthereto and locked against detachment;

Figure 4 is a -vievv similar to Fig.Y 3, but show- `ing the sheave'mounting rotated into position for assemblyon the boom or detachmenttherefrom;

Figure 5 is a detail transverse section taken on the line 5-5 in Fig.3`;

Figure 6 is a detail vertical section' through the sheaves and sheavemounting, taken on the line @-6Y of Fig. 3;

Figure 7 is a detail sec-tion taken on the line 'l-T in Fig. 2', but onan enlarged scale; and

Figure. 8-is a detailv section taken on the line 8-- in Fig'. 2.

Similiar parts are designated by the same reference characters in theseveral gures.

The improvements provided by the present invention are kapplicablegenerally to derricks or hoisting mechanism ofthe swinging boom type,but the improvements are particularly applicable to the derricks orhoisting mechanismY of wrecking trucks of the lgeneral type shown anddescribed in my prior patent hereinbefore Areferrecil to, which areyadapted for Vusenot only ,for-lifting automobiles or the like iremfvtheground or roadway,` but may Abe employed advantageously in haulingautomobiles back onto the roadfrom position at the side of the roadwhere they khave been left as the results of accidents. The invention isshown in the present instance as applied to the derrck or hoistingmechanism of a wrecking truck of that type, but it is understood thatthe invention is not to be limited to derrck or hoisting mechanism ofthis particular type, but is applicable generally to derricks orhoisting mechanisms employing a boom and hoisting and boom supportingcables which pass over sheaves mounted on the outer end of the boom.

In the present instance, the derrck or hoisting mechanism to which thepresent invention is shown applied comprises a frame I, which is adaptedto be mounted on the chassis 2 of a wrecking truck, a portion of whichis indicated at 3, this frame havin-g a boom 4 at each side which ispivoted at 5 to a bearing sleeve 6 mounted on a vertical axis 1 at therespective side of the frame, so that the boom may swing verticallyabout the pivot 5 and may swing laterally about the pivot 'I. The boomis supported and is raised and lowered by a boom-supporting cable 8,which is attached at one end to a link 9, and is adapted to be wound atits other end upon a winch I0. The link 9 is pivoted at II to a sleeveI2 so that this link may swing vertically, and the sleeve I2 is pivotedat I3 on a respective side of the frame I so that the link 9 may swinglaterally, in accordance with raising and lowering or lateral swingingmovements of the boom. The hoisting cable I4 for each boom passes over apulley or sheave I5, which is mounted on a swivel I6 on the top of theframe, one end of this hoisting cable being preferably provided with ahook I'I which may be directly engaged with the automobile or other loadto be lifted or hauled, and the hoisting cable also preferably passesaround a sheave I8 which carries another lifting or hauling hook I9,which may be engaged with the automobile or other load to be lifted orhauled. The other end of the hoisting cable I4 is adapted to be woundupon a drum mounted on the frame I. The winch I0 may be operatedmanually, as by a crank applied to the squared end 2I of its shaft, thewinch being locked against unwinding by a pawl 22 engaging a ratchetwheel 23 xed to the winch, whereby the boom may be raised and loweredand held at any desired elevation at its outer or free end. The drum 20for the hoisting cable I4 may be power driven through a power takeoff 24driven from the engine of the wrecking truck, the operation of the drumbeing effected through gearing 25 and controlled by clutch mechanism 26.The construction of the derrck or hoisting mechanism shown in thepresent instance is like that shown and described in my priorapplication, Serial No. 266,217, led April 5, 1939, now Patent No.2,264,- 569, granted December 2, 1941, and it will be understood, as isshown in that application, that a pair of swinging booms are provided,one at each side of the frame I. The sheaves on the outer end 0f eachboom, over which the hoisting and boom supporting cables pass, accordingto the present invention, differ from the sheave arrangement shown insaid prior application` Instead of mounting the sheave or the boomsupporting cable on a link attached to the outer end of the boom, asshown in that application, the boom supporting and hoisting cablesheaves, according to the present invention, are mounted coaxially onthe outer end of each boom. 'K

As shown in the present instance, the hoisting cable I4 passes over asheave 30 which is mounted centrally between the arms 3I of a fork-like75 member 32, and this sheave is journaled to ro tate freely on a shaft33, which extends transversely through the arms 3|. Also, in the presentinstance in which the derrck or hoisting mechanism is adapted for heavyduty, the boom supporting cable 8, after passing from the Winch I0,passes around a pulley 35, thence around a sheave 36, thence around asheave 31 carried by the link 9, thence around a sheave 38, and thenceto its attachment to the link 9. The sheaves 3B and 38 are journaled onthe shaft 33 at opposite sides of the sheave 30, and at the outer sidesof the arms 3| of the sheave mounting. The sheaves 30, 36 and 38 arethus all journaled to revolve freely on the shaft 33, which provides acommon axis for these sheaves. In order to prevent disengagement of theboom supporting cable 8 from the sheaves 36 and 38, guards 39 and 40 areprovided, these guards being preferably assembled on the respective endsof the shaft 33 and retained thereon by pins 4I and 42 which may extendthrough holes passing transversely through the ends of the shaft. Alsoin order to prevent disengagement of the hoisting cable I4 from itssheave 30 when this cable is slack, .a pair of guards 43 and 44 arepreferably provided which are welded or otherwise fixed to therespective arms 3| of the sheave mounting and overlie the sheave 30. Theguards 39 and 40 for the sheaves 36 and 38 are formed with flanges 45and 4B which surround portions of the peripheries of these sheaves inorder to retain the boom supporting cables in the grooves of thesesheaves when this cable is slack, portions of the flanges 45 and 46being cut away to permit the boom supporting cable 8 to pass to and fromthe respective sheaves, and in order to prevent rotation of the guards39 and 40, and thus retain the cut away portions of their flanges inpositions to clear the boom supporting cable, a portion of the flange ofeach of these guards is extended to form a lug 41, which is providedwith a notch 48 adapted to straddle a rib 49, which projects from theouter side of the respective arm 3| of the sheave mounting.

The sheave mounting is swivelled in the outer end of the boom so that itmay rotate about the longitudinal axis of the boom when the hoistingcable exerts a lateral stress upon the boom, as when pulling anautomobile or other load at an angle to the longitudinal center line ofthe wrecking truck. For this purpose, the sheave mounting is formed witha stem or spindle 50, and the boom, or at least the outer end thereof,`is of Atubular formation, so that the stem or spindle of the sheavemounting may be introduced into the outer end of the boom. The stem orspindle is preferably formed with a shoulder 5I to form a bearing in theouter end of the boom, and about which the sheave mounting may swivel,and the inner extremity of the stern 5I) is formed with a cylindricalflange 52, which is also adapted to have a bearing within the tubularouter end of the boom. A portion of the periphery of the ange 52 is cutoff or interrupted as indicatedat 53,Y and a lug 54 is provided on thestem 59 at the same side thereof on which the cut-away portion 53 islocated, the lug 54, however, being located at a different point axiallyof the stem' 50. The tubular outer end of the boom is provided with alocking means which projects into the boom and is adapted to cooperatewith theflange 52, such locking means comprising preferably a pair ofstuds 55 which may be welded or otherwise secured in holesfdrilled intothe tubular outer end of the boom. The flange 52 vand locking lstuds 55are so related that when the Vsheave mounting is rotated into theposition shown in Fig. l, the cut-away portion ofthe flange 52 will passinwardly beyond the lock-ing studs 55, so that the sheave mounting,while rotated into such a position, may be readily assembled in theouterend of the boom or removed therefrom should such become necessary, andwhen the sheave mounting is rotated into the position shown in Fig. 3,which is its normal position, the uninterrupted portion of the flange 52will assume a position at the inner side of the locking studs 55, andwill thereby lock the sheave mounting against Withdrawal from the outerend of the boom, and when the sheave mounting is in such normalposition, the stud 54 will bear on the upper side of the surroundingwall of the boom and in cooperation with the shoulder 5I, will provide abearing on which the sheave mounting may swivel in the outer end of theboom and on the longitudinal axis thereof.

The sheave mounting swivels in the outer end of the boom under controlof a guide 56 for the hoisting cable I4, this guide being preferably inthe form of a loop, the upper ends of which are suspended from thesheave-supporting shaft 33, and the lower portion of which is providedwith a pair of cable guiding members 5l, it being understood that if theload being lifted or pulled is not directly beneath the sheave S, but isat either side thereof, the tension on the hoisting cable I4, actingthrough the guide 56, will rotate the sheave mounting in the outer endof the boom, under the influence of the tension on the hoisting cable I4.

When, as shown in the present instance, the derrick or hoistingmechanism comprises a pair of swinging booms, the booms are eachprovided with the sheave mounting, as just described, and means isprovided for locking the booms together to prevent swinging movementthereof while a load is being pulled from a side of one or the other ofthe booms. As shown in the present instance, the outer ends of the boomsare provided with arms 5l) and 6i whichextend toward one another, thearm GI being forked, as shown in Fig. 7 to receive the end of the otherarm 60, and a locking bolt 62 is provided on the arm 6| and is adaptedto engage, under the action of a spring 63, in holes in the inner endsof the arms 60 and 5| and thereby lock the booms together, as shown inFig. 2. Each of the arms 60 and 6l is preferably formed with asleeve-like portion 60a which is slidable onto the outer end of therespective boom, and may rotate thereon and thus avoid strain while aload is applied to one or the other boom. When the booms are lockedtogether, lateral swing of either boom is prevented, and the hoisting orservice cable lll of either boom may then be employed for pulling a loadtoward the wrecking truckV from either side thereof while the truck isstanding lengthwise of the road, and the booms extend toward the rear ofthe truck. When the booms are locked together, and an angular pull fromthe rear takes place, any tendency to pull the Swivel sheave mounting 32out of the end of the boom will be prevented by the engagement of theiiange 52 with the locking studs 55, these parts occupying the positionshown,l in

as the swivel sheave mounting abuts against the outer end of thesleeve-like-portion Gila of the respective locking arm 60 or 6l, pullingof the locking arm off of the end of the respective boom is prevented.

Although the improved sheave mounting is shown and described as appliedto a derrick or hoisting mechanism in vwhich two sheavesA are providedwith four lines of boom-supporting cable, it will be obvious that theinvention is applicable to booms employing two lines of boomsupportingcable, in which case one of the sheaves for 'the boom-supporting Vcablemay be omitted.

I claim:

1. In hoisting apparatus, the combination of a boom, a sheave mountingswivelled in the outer end of the boom for rotation about itslongitudinal axis,ahoisting cable andaplurality of pairs of lines of aboom supporting cable, an inner sheave for the hoisting cable and a pairof outer sheaves for the boom supporting cable, and a shaft supported bysaid mounting and on which said sheaves are journaled on a common axistransverse to the longitudinal axis of the boom.

2. In hoisting apparatus, the combination of a pair of booms, means forlocking together the outer ends of the booms, boom supporting andhoisting cables, and sheaves for said cables, a sheave mountingswivelled in the outer end of each boom for rotation about itslongitudinal axis, and a shaft supported by each of said mountings on anaxis which intersects the longitudinal axis of the respective boom andon which the respective sheaves are journaled as a common axis.

3. In hoisting apparatus, the combination of a boom and boom supportingand hoisting cables, a forked sheave mounting swivelled in the outer endof the boom for rotation about its longitudinal axis, a sheave for thehoisting cable journaled in the fork of the mounting, and a pair ofsheaves for the boom cable journaled on the mounting at opposite sidesthereof and coaxially with the sheave for the hoisting cable andequalizing the boom supporting cables at opposite sides thereof when themounting swivels about the longitudinal axis of the boom.

4. In hoisting apparatus, the combination of a boom and boom supportingand hoisting cables, a forked sheave mounting swivelled in the outer endof the boom for rotation about its longitudinal axis, a sheave for thehoisting cable journaled in the fork of the mounting, a pair of sheavesfor the boom cable journaled on the mounting coaxially with the sheavefor the hoisting cable and at opposite sides thereof, and guards mountedat the outer sides of the sheaves for the boom cable and havingprojections thereon cooperative with the respective sides of the boom toprevent rotation of the guards.

5. In a wrecking truck having a pair of booms mounted to swing thereon,means for locking the Figure 3 under normal operating conditions, and 75booms together, and boom supporting and hoisting cables, a sheavemounting swivelled in the outer end of at least one of the booms forrotation about its longitudinal axis, sheaves for the boom supportingand hoisting cables, and a shaft supported by the sheave mounting onwhich said sheaves are journaled on a common axis which intersects thelongitudinal axis of the boom, and a guide for the hoisting cableconnected to the sheave mounting for swinging the latter and the sheavesthereon about the longitudinal axis of the boom under a pull appliedlaterally of the boom by the hoisting cable.

6. In hoisting apparatus, the combination of a boom having a tubularouter end,V boom supporting and hoisting cables, sheaves for saidcables, a sheave mountingV supporting said sheaves and having a portionrotatably and removably extending into the tubular outer end` of theboom, and means for locking said mounting in the tubular outer end ofthe boom While said mounting is in its normal position 'and forunlocking the mounting therefrom when rotated out of said position.

7. In hoisting apparatus, the combination of a boom having a tubularouter end, boom supporting and Vhoisting cables, sheaves for saidcables, a sheave mounting on which the sheaves are journaled and havingastem swvelled in the tubular outer: end of the boom, and provjectionson said stem and in the tubular outer end of the boom cooperative whilesaid sheave mounting is in its normal position to lock said mountingfrom axial displacement but relatively movable to release the mountingfor removal when the latter is rotated out of said normal position.

ERNEST WALTER. HOLMES.

